This invention relates generally to techniques for inspecting glass vessels or containers and more particularly to a glass container inspection apparatus installed in the production line of glass containers such as glass bottles and jars and adapted to cause an impact rod to drop freely from a specific height into each glass vessel thereby to test the strength of the bottom of that glass vessel.
During the production process of glass containers, cracks are sometimes formed in a part of the glass or gas bubbles or some other matter become mixed with the glass in some instances, and these defects remain in the glass until the containers are formed. Since the mechanical strength of glass containers having such defects tends to be low and is unreliable, it is necessary to carry out inspection of all glass containers at an intermediate point in their production line and to reject any which are found to have such defects. In order to carry out an inspection of this nature, it has been a common practice heretofore to introduce pressurized water into each glass container to be inspected through its mouth thereby to apply water pressure to the interior of the container to test its strength.
In this conventional testing method, however, the glass container must be filled with pressurized water, whereby an elaborate testing apparatus must be installed, and a long time is required for the test. For this reason, it is extremely difficult to apply a test of this nature with respect to each and every glass container on the production line, that is, to carry out a 100-percent inspection. Therefore, it has heretofore been unavoidably necessary to resort to spot-checking tests, whereby there has been the possibility of defective items existing in the lots of finished products.
Accordingly, in order to solve this problem, we have previously provided an apparatus (as disclosed in the specification of Japanese Patent Laid Open No. 129283/1976) for testing the strength of glass containers by causing a rod to descend toward the bottom of each vessel through the mouth thereof so that its lower tip abuts against the center of the bottom surface of the container thereby to apply a static load to the bottom surface.
However, this previous apparatus for testing glass containers was still inadequate for actual use in combination within a production line for continuously producing glass containers in large quantity. More specifically, in order to reduce a glass container inspection apparatus to practice, the glass container strength test must be carried out continuously in an intermediate part of the glass container production line. Furthermore, the apparatus must be made adjustable in accordance with the dimensions, particularly the height or depth, of the glass containers being produced.